Dwelling houses and other structures made for human occupancy usually include a sloped roof structure with an attic space between the roof structure and the dwelling rooms therebelow. The dwelling rooms usually are heated and cooled to maintain a desired temperature range of between approximately 68.degree. F. and 74.degree. F. which is comfortable to the occupants, but the temperature of the attic space varies widely, from very low temperatures in the winter months to very high temperatures during the summer months. Thus, the temperature gradient from the dwelling rooms, across the ceiling to the attic frequently is high. Also, a similar temperature gradient usually is present from the inside wall surfaces to the outside wall surfaces of the dwelling. The rate at which heat will flow through the ceiling and walls into or out of a room is dependent upon at least two factors: the difference between the temperature inside the room and the temperature outside the room, and the efficiency with which the ceiling, roof, walls and flooring of the building between the high and low temperatures conduct heat. In order to reduce the rate of heat flow into or out of the room, it is typically the practice to provide insulating materials in the walls and ceiling of such buildings. Such insulating materials include mineral wool, urethane foams and the like which are well known in the art.
The ceiling of a room is a particularly important area for insulation because the majority of the heat transfer takes place through the ceiling. This is true because during summer, attic temperature may reach as high as 150.degree. F., even though outside temperatures are approximately 90.degree. F., due to radiation heating, while the temperature of the rooms below the ceiling are maintained close to 70.degree. F., sometimes resulting in a temperature gradient across the ceiling of more than 70.degree. F. Furthermore, during winter seasons room temperature of 80.degree. F. adjacent the ceiling is often required to provide an overall temperature of 72.degree. F. in the room below, while the temperature in the attic may be below freezing, resulting in a temperature gradient across the ceiling of about 50.degree. F.
Although providing conventional insulating materials in the walls and on the attic floor of a building is effective at reducing heat transfer through the walls and ceiling, the insulation materials are expensive, are bulky to handle and to install, and in some instances are not very effective.